Discharge-valve for elastic-fluid compressors.



J. ALLAN.

DISCHARGE VALVE FOR ELASTIC FLUID OOMPRESSORS.

APPLICATION FILED JULY 26, 1909,

956,789. Patented May 3,1910.

JGMQS A an, Qvwentoz,

. zen of the United States, and a resident of following. is a specification.

"closed position after having been opened,

' Fig. 1.

TUNTTED STATES PATENT JAMES ALLAN, OF OMAHA, NEBRASKA, ASSIGNOR TO LARSEN-BAKER ICE MAGHINE 00., A CORPORATION OF NEBRASKA.

DISCHARGE-VALVE FOR ELASTIC-FLUID CGMPRE SSOPSP Specification of Letters Patent.

' Patented May 3, react Application filed July 26, 1909. Serial No. 509,743.

To all whom it may concern; l Be it known that I, Janus ALLAN, a citi- Omaha, in the county of Douglas and State of Nebraska, have invented certain new and useful Improvements in Discharge-Valves for Elastic-Fluid Compressors, of which the My invention relates tocompressors for air, ammonia or other elastic fluids, and especially to the discharge valves for such machines.

It is the object of my invention to provide a valve for the above purposes in which the opening movement thereof may be cushioned without retarding the rapid closing of the valve when the llow of gas. through the same has ceased, to prevent the return of any of the compressed fluid to the compressing cylinder.

Constructions embodying my alIlYGl'ltlOll are illustrated in the accompanying drawings, in which Figure 1 is a vertical sectional view through thevalve mechanism showing the valve in closed position, Fig. 2 is a similar view showing the valve approaching the and Fig. 3 is a t t\I1S\'1S section of the valve casing on the plane of the line ;r'.r of

Referringto the drawings. 1 represents a portion of the cylinder-head of an elastictluid compressor, the lower side thereof being that adjoining the compressing cylinder, and the space? therein being the dis charge chamber into which the compressed fluid is forced and to which the passage from the cylinder is controlled by the discharge valve. The valve 3 when closed rests uponza removable valveseat 4 which is disposed within a shouldered recessformed in the head 1, as shown. The valve-seat is hcldin position in the recess by the cage or casing 5 which extends up through the dis charge chamber 2 and has arranged overfthe top thereof the dome-cap 6 whichis secured to the head 1 by means of the studs 7.

\Vithin the dome-cap is a chamber 8 and at the lowerside thereof is an annular lip 9 which extends into a recess formed partly in the head 1 and partly in the valve casing 5, a gasket 10 of suitable material being arranged in the recess under the lip, 9. The

valve casing 5 has a cylindrical chamber.

formed in the lower part thereof and in the sides thereof are suitable ports connecting said chamber with the discharge chamber 2 in the head 1. The stem 11 0; the valve passes up through a suitable guide 12 which depends into the said cylindrical chamber in the valve casing, and around the guide is disposed a helical coil spring 13'which engages'the valve to hold the same normally in closed position.

I v In the upper end of me casmg o is vformed the cylinder for the cushion-piston 14. The upper end of said cylinder is closed by the screw-plug 15, which extends up into the chamber 8 in the dome-cap, and through the center of which is made a small vent 16 which forms a restricted pas sage connecting the cylinder and the chamberS. A vertically extending port 17 forms a connection between the chamber Sand the chamber in the lower part at the casing 5.

A port 18 intersects the port 17 and connects the same with the cushion cylinder at a point slightly above the top of the piston when the same is in its lower position shown. in Fig. 1. A p rt 19 connects the lower end of the cushion cylinder with the chamber in the lower part of the casing 5. The upper end of the valve-stem 11 is made of slightly smaller diameter than the main part thercot', and on the lower side of the cushion piston 14 is a short stem adapted to abut upon theupper end of the stem 11.

\Vhen the valve is in closed position and the cushion piston is in the lower position with the stem thereof engaging the valve stem, as shown in Fig. 1, upward movement oi the valve in opening actuates the cushion piston, and after the same has moved far enough to close the port 18 a gas cushion is formed in the upper part of the cylinder which retards the upward movement of the valve by slightly increasing the downward pressure thereon until the pressures have be come equalized by the escape of gas from the cylinder through the vent 16. hen the movement of the compressed fluid past the .valve ceases, the valve-may be returned very quickly to its seat by the pressure of the spring 13, its movement not being retarded by the cushion piston, which is left at the upper end of the cylinder as shown in Fig. 2.

After the valve has returned to its seat and while it remains closed and before-its next period ofopening, the cushion piston returns cylinder when the valve is to its lower position, being actuated by gravity, and the pressures upon'the upper and lower surfaces thereof beingeqiialized through the vent l6 and the ports 17 and 19.

Now, having described my invention, What I claim and desire to secure-by Letters Patent is: I

1. In a discharge valve mechanism for elastic-fluid compressors, in combination, a valve, a stem thereon, a piston abutting upon said stem but not rigidly connected therewith, and means forming a chamber at the end of the piston opposite the valve, there being ports arranged to permit a relatively slow equalizing of pressures upon the ends of the piston, whereby the opening of the valve will be retarded and the closing thereof unretarded by the piston.

2. In a discharge valve mechanism for elastic-fluid compressors, in combination, a cylinder, a piston movable therein, a valve having a stem adapted to engage the piston and move the same toward one end of the opened, and a casing inclosing the valve and piston, there being ports in said casing communicating With each end of the cylinder, said ports being so proportioned as to retard the escape of gas from the end of the cylinder opposite the valve stem but not to retard the escape from the end of the cylinder adjoining the valve stem,and the relation of the piston and valve stem being such that the same may separate when the Valve closes, for the purpose described.

3. In a discharge valve mechanism for elastic-fluid compressors,'in combination a valve, a vertically disposed cylinder, at piston movable therein, the cylinder being adapted to retard movement of the piston therein, and means connecting the valve and piston whereby the piston may be raised by the valve, but said connecting means being separable so that the valve may not actuate the piston downwardly.

4. In a discharge valve mechanism for elastic-fluid compressors, in combination, a valve, a cylinder, a cushion in said cylinder, the cylinder being arranged to permit a relatively piston therein, and separable means connecting the valve and piston whereby the piston will retard movement of the valve in one direction but not in the other direction.

5. In a discharge elastic-fluid compressors, in combination, a valve, a valve stem, a casing, a guide formed by the casing, a spring engaging the valve to actuate the same toward its seat, a cylinder formed in the casing, a piston movable in said cylinder and engageable by the valve stem, and a cap having a vent therein to permit a restricted escape of gas from the end of the cylinder opposite the valve stem,

whereby the piston may retard opening of s the valve but not retard the closing move ment thereof, and the piston return slowly to reengagc the valve stem while the valve remains closed.

In testimony whereof I have hereunto subscribed my name in the presence of two witnesses.

' JAMES A LLAN.

lVitnesses R01 G. Kiu'rz, l). O. BARNELL.

piston disposed slow movement of the valve mechanism for r 

